A cellphone provider has the business objective of wanting to estimate the proportion of subscribers who would upgrade to a new cellphone with improved features if it were made available at a substantially reduced cost. Data are collected from a random sample of 500 subscribers. The results indicate that 140 of the subscribers would upgrade to a new cellphone at a reduced cost. Complete parts(a) and(b) below.

a.) Construct a 95% confidence interval estimate for the population proportion of subscribers that would upgrade to a new cellphone at a reduced cost.

_____ _____ (Round to four decimal places asneeded.)

b.) How would the manager in charge of promotional programs use the results in(a)?

A.

The manager can infer that 95% of subscribers that would upgrade to a new cellphone at a reduced cost.

B.

The manager can infer that the true population proportion of subscribers that would upgrade to a new cellphone at a reduced cost is somewhere in this interval 95% of the time.

C.

The manager can infer with 95% confidence that the population proportion of all subscribers that would upgrade to a new cellphone at a reduced cost is somewhere in this interval.

D.

The manager can infer with 95% confidence that the proportion of subscribers in the sample that would upgrade to a new cellphone at a reduced cost is somewhere in this interval.